Copper is a better conductor than gold, and it's lighter. Gold doesn't corrode. So only if you're concerned about corrosion, you'd go for gold. In all other cases, you go for copper. Hence, you'd expect gold to be cheaper than copper if both are equally abundant and gold isn't used as store of value.
I've been told by a metallurgist that for wire gold plated copper is best, but for things like pipes where you care about corrosion gold rules. Now compare the weight of the average pipe to the average wire and tell me again why gold should be cheaper.
You cannot use something as a store of value if it is not in fact valuable. If you could I would use my poo as a store of value and be a rich man.